Apparatus for treating wood pulf or the like with chemical reagents



July 18,1939. c. a. THORNE 2,166,200

APPARATUS FOR TREATING WOOD PULP OR THE LIKE WITH CHEMICAL REAGENTS Filed May 12, 1938 Patented July 11.5, 1939 PATENT OFFICE APPARATUS FOR TREATING woon PULP on THE LIKE wrrn CHEMICAL as AGENTS Carl Busch Thorne, Hawkcsbm-y, Ontario,

' Canada Application May 12, 1938, Serial No. 207,48!

4 Claims.

This invention relates to "apparatus for the treatment of fluid materials with reacting chemicals in which uniformity of contact within the period of reaction is an important consideration.

The invention will be described with reference to the accompanying drawing in which Figure 1 is a sectional elevation and Figure 2 a cross section of apparatus for continuous operation, and

Figure 3 is a sectional elevation partially broken away and Figure 4 a cross section of apparatus arranged for batch operation.

, In the drawing l is a tank, which is preferably circular but may be more or less oblong in cross section, and 2 an inside concentric pipe which may be elongated in cross section instead of circular as shown. The annular chamber within the tank I is provided with a helical channel 3, which may extend for the full length of the chamber as shown or for only a portion of the length, preferably adjacent the feed end of the chamber. This channel is formed by a partition 4 extending spirally within the annular chamber and contacting its wallsand that of the pipe 2.

flights of this partition may be employed to vary the length of the channel 3 as well as its height within the chamber.

Adjacent the top of the pipe 2 are one or more openings 5 connecting the annular chamber with that of the pipe. An outlet 6 which may be a relief valve is provided at the top of, the tank for the escape of air or the relief of pressure and the inlet 1 provides for the admission of steam or the like as desired.

As shown in Figures 1 and 2 a pipe 8 having a valve 9 connects the annular chamber with the discharge side of a pump ID, the suction side of which is connected to a fluid material supply manner as illustrated in Figure 1 20 and 20" being fingers on the float stem and 2| and 2| electric switches connected to a reversible motor 22 operating through a speed reducer 23 to the valve.

through pipe II and a chemical reagent supply trols operation of the valve H in any well known 1 In operation paper pulp, for example, is drawn through pipe II and bleaching, cooking or other chemical through pipe l2 from respective sources of supply and passing through the pump are mixed and forced into the tank I more or less tangentially of the partition 4, as shown in Figure 2. The mass of the reacting mixture is compelled to follow the helical channel 3 and reaching the outlet 5 flows into the pipe 2. When this chamber is filled the float valve operates the switch to start the motor 22 which in turn opens the :valve ll to deliver the pulp from the tank for washing or further treatment. The rate of feed by the pump l0 determinesthe maximum length of the reaction period within the tank and the helical channel insures maximum uniformity of contact between the fluid material and the chemical reagent. Any desired pressure may be maintained within the tank by the admission of steam or the like through pipe I or otherwise in any known manner.

In the arrangement shown in Figures 3 and 4 the discharge pipe 25 from the chamber 2 is connected to pipe 26 having a valve 21 at the suction side of the pump 10 and is provided with a manually operated valve 28. The tank I is preferably placed above a suitable stock chest 29 into which i it discharges through valve controlled outlet 30. The stock chest may be provided with agitating means not shown.

.In operation the pulp or other fluid material is pumped into the annular chamber as before described valve 28 being closed. When the tank is .full valve 2'! is closed and valve 28 opened and pump l0 circulates the reacting mass in uniform mixture through the tank for such period as is required to complete the desired reaction. The material is then discharged into the stock chest through outlet 30.

It will be observed that the apparatus is capable of flexibility of operation which may be adjusted to suit the requirements of the various materials to be treated therein and conditions will determine the preferred operation to be used in each case. For example, it is contemplated that the reacting mass of fluid material may be admitted to the central pipe 2 and discharging therefrom through the opening 5 may flow downwardly through the helical channel 3 to be discharged from the tank I. Should this channel not be continued for the full length of the tank it is preferably located at the inlet end of the annular chamber. The relative capacity of the central chamber and the annular chamher may .vary with diflerent materials under treatment.

The apparatus insures adequate mixing of the pulp and chemical reagent and continuous movement ot'all the mixture without channelling or short circuiting by the incoming stream, thus insuring uniformity of reaction throughout the mass of the mixture.

I claim: 1

1. Apparatus for treating paper pulp and the like with reagents which comprises a cylindroidal tank, a pipe vertically and concentrically located within the tank and forming an annular chamber therein, a confined helical channel within the chamber and extending around said pipe upwardly from the bottom of the chamber to provide a long reaction zone for said pulp and reagent, a feed inlet for said channel adjacent the bottom of the chamber, a discharge outlet for said channel communicating with said pipe adjacent its upper end and a discharge outlet for said pipe adjacent the lower end of said chamher.

2. Apparatus for treating paper pulp and the like comprising a cylindroidal tank, an inner chamber vertically and substantially concentrically located within the tank and communicating with the latter at its upper end only, a confined helical channel formed around the inner chamber and occupying the space within the tank external to said chamber, a feed inlet for said channel adjacent the bottom 01 the tank and a discharge outlet for said inner chamber adjacent its lower end.

3. Apparatus for treating a mixture of paper pulp or the like and reagents comprising a cylindroidal tank, an inner chamber vertically and substantially concentrically located within the tank and communicating with the surrounding space in the latter at its upper end only, a. confined helical channel formed around the inner chamber and occupying said surrounding space to provide a long reaction zone for said mixture, the lower ends of the inner chamber and the helical channel each being provided with a port for said mixture, and means for circulating said mixture through said ports and reaction zone.

4. Apparatus for treating a mixture of paper pulp or the like and reagents comprising a cylindroidal tank, an inner chamber vertically and substantially concentrically located within the tank and communicating with the surrounding space in the latter at its upper end only, a confined helical channel formed around the inner chamber and occupying said surrounding space to provide a long reaction zone for said mixture, a feed inlet for said channel adjacent the bottom of the tank, a discharge outlet for said inner chamber adjacent its lower end, and means for forcing said mixture through said reaction zone.

CARL BUSCH THORNE. 

